Features of river flounder and description of freshwater fish

One of the most amazing bottom dwellers is flounder. Sea fish or river fish cannot be solved right away, because it has expanded the range from ocean depths and sea coasts to freshwater rivers. In the course of evolution, the river flounder acquired a special eye position and learned to disguise itself by hiding from predators.

Adaptation to difficult living conditions gave it interesting properties, which can be found by reading the description of the fish.

Flounder lives both in the deep sea and in shallow rivers

Since flounder has an unusual shape and specific features, it is difficult to confuse with other fish. Different species have common features:

the body of mature individuals of a rhomboid shape or in the form of an oval, is flat;

eyeballs are on one side of the body;

fins pinnate, fused, rounded;

small tail extended to the end;

the color of the side on which the eyes are located repeats the color of the natural habitat for camouflage, and the belly (“blind” side) – of a lighter shade and without a pattern;

the body of the fish is covered with small scales.

Flounder eyeballs are on one side of the body.

Eyeballs can perform multidirectional movements, each eye operates autonomously. That visual organ is especially mobile, which, due to a metamorphosis, has moved to the other side.

There are some differences in the appearance of river and sea flounder. Yielding to the sea species in size, the river can reach up to half a meter in length, and weigh about 3 kilograms.

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Flounder has a wide range, including seashores, rivers and some lakes. Shallow water is a favorite place for this fish, where it waits for prey buried in the sand. A little less, it occurs at a depth of 50 meters.

River species found in the Mediterranean and on the coast of Central Europe and Scandinavia, but it can also be found in reservoirs from Norway to North Africa.

It is perfectly adapted to life in both salt and fresh water, so many people cannot figure out what kind of flounder a fish is – river or sea. The most comfortable conditions for it are brackish water bays.

During spring spawning, the river species migrates to saline reservoirs. Due to the large-scale spawning in the Baltic waters, the flounder in our country was named Baltic.

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Flounder leads a solitary and sedentary lifestyle, numerous groups are formed only during the breeding season. This bottom dweller spends most of the time buried in the sand and waiting for prey. Possessing impressive skills of mimicry, flounder can completely repeat the pattern of pebbles on the bottom, merging with the environment.

But this is a long process — it takes about 2–3 days for the fish to change successfully.

Of particular interest is the way in which this fish swims. It moves in the water like a ramp, making smooth, wavy movements with its body. The pectoral fins help her to change direction.

The special structure of the gills helps to hide from enemies. In case of danger, the flounder with a force releases a stream of water through the gill openings located on the belly, lifts dregs from the bottom, which allows it to escape.

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Flounder refers to predators. It feeds on mollusks, crustaceans, worms, small species of fish, and benthos. This denizen has strong teeth and powerful jaws, therefore, without much effort can cope with creatures that have armor.

In particular, these fish like sertsevidki who have a very durable sink.

River flounder can live for 20–25 years, but rarely reaches that age, as it is a commercial fish. It becomes sexually mature in 3−4 years and in February-May is sent to spawn.

To do this, the fish goes to sea, overcoming vast distances. Salt water is an important factor in its reproduction. If spawning occurs in a freshwater body of water, the larvae will sink to the bottom and die.

Fresh oxygen is necessary for caviar development, such conditions are possible only in water with a salinity of more than 10 ppm.

River flounder can live for 20–25 years, but rarely reaches that age, as it is a commercial fish.

Flounder spawns up to 2 million eggs at a depth of 25-40 meters. They swim for a while near the surface.

After about 11 days, the larvae hatch. They feed on plankton and other small organisms near the surface.

When the fish grows up, it releases air from the swim bladder and lies on the bottom, usually on the left side. At the same time, the body begins to change – the left eye moves, and the skin on the upper side darkens.

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The description of the flounder does not fully disclose all of its amazing abilities and entertaining facts.. Here are some of them:

This fish was found even in the Mariana Trench – in a place with tremendous pressure, where other species are not able to survive.

In most cases, the eyes of the flounder are located on the right side of the body, but non-standard individuals are also found.

The lateral position of the head helps it gnaw mollusks directly from the ground.

She masterfully changes her color. If you put a chessboard on the bottom, it will be covered with symmetrical dark and light spots.

Mimicry is subject only to sighted fish. A blind fish loses its ability to disguise itself.

In most cases, the eyes of the flounder are located on the right side of the body.

The skeleton is better developed in the upper body.

Kambalov can interbreed with each other and then the offspring acquires the features of both parents belonging to different species.

The skin on the lower side of the individual is more durable, it protects the fish from damage on the stones and the ground.

Flounder meat is considered an aphrodisiac.

Tender meat and lack of bones make flounder dishes quite popular. Meat is valued for its beneficial properties and taste with a low calorie content and is often used in therapeutic diets.

You can cook in various ways: soar, boil, fry, smoke, bake. However, in order to preserve the taste and beneficial substances, it is recommended to apply gentle processing.